Polyvinyl chloride resins are widely used to produce a variety of products which are found in every day life. While such polyvinyl chloride-containing products may be uncolored, it is usually desirable to impart a color to the product so that they are pleasing to the eye. Various colorants have been used to accomplish this and these basically fall into two categories: dyes (which are soluble in vinyl formulations) and pigments (which are insoluble in vinyl formulations). The latter materials have been the predominantly used colorants for a number of reasons: (a) they generally have good light fastness; (b) for the most part they can withstand the relatively high temperatures to which the vinyl formulations are subjected; (c) and, with certain exceptions, they do not migrate or bleed. On the other hand, the conventionally used dyes for polyvinyl chloride, which primarily are disperse dyes, tend to show all of these detrimental characteristics, and their use has been quite limited.